1. Field of the Invention
A missile launch rail experiences a harsh environment that produces many stresses in the material. This subsequently results in fatigue failures. These stresses can be caused by vibration, bending, and overuse. When failures occur in the form of cracks in the latch pinholes or rail pinholes, catastrophic failures such as a hang fire can occur.
2. Discussion of the Background
The missile launch rail was designed for a finite life measured in missile firings and captive carry vibration hours. The hours and firings needed to be monitored and tracked so that the missile launch rail could be replaced on time. Tracking the life of the rails in combat has proved to be difficult and unfeasible.
When catastrophic failures on a missile launch rail have been discovered, two assumptions have been made about the causes of the cracking: a) there was a coupled vibration between the missile launch rail and the missile, and b) equipment on both the missile and the missile launch rail was stressed.
Several solutions were considered to address the rail pin hole and/or latch pin hole crack. A redesign of the rail would be costly and time consuming. The cracking needs to be addressed quickly because of the missile launch rails currently in use by the Army. Currently, the missile launch rails are being inspected using Non-Destructive Inspection (NDI) methods, but in order for NDI methods to find all of the rail pin hole and/or latch pin hole cracks the rails must be disassembled. The disassembly causes the inspection to be time consuming and costly. A solution for missile launch rail cracking is an immediate issue.
In FIG. 1 (Prior Art), the existing missile launch rail latch technology does not have a failsafe in the event of a failure. The rail pin holes 132 in the missile launch rail 110 are very close to the edge of the rail 110, thus not adhering to sound engineering principles. The missile launch rail 110 holds the missile in place and supports and secures the components of the latch 114. The latch pin 112 inserted through the rail pin holes 132 in the missile launch rail 110 and the latch pin holes 134 in the latch 114 provides the pivot for the latch 114 as the latch 114 moves with the missile. The latch 114 is the mechanism that holds the missile on the missile launch rail 110. The latch handle 116 allows for controlling the latching and unlatching of the missile. The latch cam shaft 118 positions the latch 114 in the latched or unlatched configuration according to whether the flat side 140 or the rounded side 142 of the latch cam shaft 118 is under the cam end 136 of the latch 114. The latch spring 120 provides tension under the latch 114 at the spring end 138 of the latch 114 as the spring end 138 is pushed down on the latch spring 138.